Implementation of a Nonisothermal Unified Inelastic-Strain Theory into ADINA6.0

摘要

Simulations with many modern aerospace materials require realistic mechanicalresponse models for use in isothermal and nonisothermal applications. One such model is a unified inelastic-strain theory which has been applied to capture the strain-rate sensitivity and time dependent behavior of the titanium alloy Timetal 21S (formerly B21S). The Bodner-Partom form of unified theory satisfactorily describes the B21S stress-strain response for a range of temperatures from 23 deg C and 815 deg C and strain rate from 10 3/S to 1.X10-7/S. Practical use of the theory in finite element applications depends on advanced numerical algorithms that rapidly solve the inherently 'stiff' constitutive equations. Special 'user-defined' subroutines provide the framework for the incorporation of these numerical algorithms into ADINA6.0, a general purpose finite element package. This user-guide contains a brief overview of the theory, the B21S material parameters, subroutine structure, variable nomenclature, and numerical algorithms. Test cases are described to illustrate the numerical integration schemes and provide guidance for error management. The appendices contain hard-